Not Applicable
Not Applicable
Not Applicable
1. Field of the Invention
This invention relates to the field of ladders. More specifically, the invention comprises a modular ladder having removable steps.
2. Description of the Related Art
The incorporation of removable rungs into various structures is well known in the prior art. As one example, U.S. Pat. No. 6,247,553 to Jones (2001) discloses a removable rung (or step) designed to be applied to a steel T-post of the type commonly used for cattle fencing. It allows a user to step over a modern fence line without having to put weight on the strands of barbed wire. The Jones device is not easily removable, however. It is designed to be installed and left in place. Thus, it is ill suited for the type of application encompassed by the present invention.
U.S. Pat. No. 3,833,090 to Georgianna (1974) discloses a removable step designed to be locked into a steel support column. This invention is directed to warehouse racks, whose vertical columns already include slots for the mounting of shelves and the like. The step design in the ""090 patent takes advantage of these pre-existing slots. The step is quite large and cumbersome, however. It would be difficult to store a set of such steps on the user""s person, and quite cumbersome to carry them over long distances.
A similar device is disclosed in U.S. Pat. No. 4,450,936 to Strom (1984). The Strom device also takes advantage of the pre-existing slots found in warehouse columns. Unlike the Georgianna device, though, it is formed of simple bar stock components. The ""936 device should therefore be easier to fabricate. It is still quite bulky, however. In addition, it requires a support column having a large interior cavity so that the step can be xe2x80x9csnakedxe2x80x9d into position. While such a large cavity is often found in warehouse columns, it is rarely found elsewhere.
Accordingly, the prior art devices are limited in that they:
1. Are difficult to apply and remove;
2. Are heavy;
3. Are bulky; and
4. Require a vertical column having a large interior cavity. Require the deployment
A ladder is composed of a vertical support structure and a set of rungs. In the present invention, the vertical support structure is formed by stacking a series of interlocking sticks. The sticks incorporate features allowing the removable installation of a set of rungs. The rungs are small and light, so that a set of such rungs may be easily carried by a user. The vertical sticks generally remain attached to the object to be climbedxe2x80x94such as a tree or pole. When the user wishes to climb the object, the user installs the rungs as he or she climbs. The rungs are then removed upon descent. In this manner, unauthorized climbing of the object is inhibited.
Several different embodiments of the removable rungs are disclosed. The common feature of all these embodiments is the fact that the rungs cannot come loose from the vertical stick while they are under load. The application of the invention to different types of hunting tree stands is also disclosed in detail, although the application of the invention extends far beyond hunting products.